Malignant tachyarrhythmia, for example, ventricular fibrillation, is an uncoordinated contraction of the cardiac muscle of the ventricles in the heart, and is the most commonly identified arrhythmia in cardiac arrest patients. If this arrhythmia continues for more than a few seconds, it may result in cardiogenic shock and cessation of effective blood circulation. Consequently, sudden cardiac death (SCD) may result in a matter of minutes.
During a malignant tachyarrhythmia event, the use of an Automatic External Defibrillator (AED) system has been shown to be beneficial at preventing SCD. An AED uses strategically placed electrodes to provide one or more defibrillation electric pulses to the heart of a subject. Because of the large energies of the defibrillation electric pulse, the electrodes may benefit from reduced impedance and increased surface area contact at the electrode/skin interface to reduce potential damage of the body tissue of the subject and to facilitate delivery of the electrical pulse therapy. Low impedance interface fluids may be used to reduce impedance and increase surface area at the electrode/skin interface. For a wearable AED (WAED), it may be desirable for the low impedance interface fluid to be dispensed at the electrode/skin interface automatically. Such systems may involve bulky or uncomfortable low impedance interface fluid dispensing units near the electrodes and/or pumps to deliver the low impedance interface fluid to the electrode/skin interface before delivering one or more defibrillation electric pulses to the heart of a subject.